Key to studied Stachys taxa, based on nutlet morphological and anatomical characters
1. Nutlet color is brown, dark brown or dark brown-black ....................................................................................................................2
1. Nutlet color is taupe..........................................................................................................................................................................11
2. Nutlet color is brown ..........................................................................................................................................................................3
2. Nutlet color is dark brown or dark brown-black ................................................................................................................................9
3. Nutlet shape is ovatus, ovatus-rectangularis or ovatus-triangularis ...................................................................................................4
3. Nutlet shape is ellipticus............................................................................................................ S. megalodonta subsp. megalodonta
4. Ovatus-triangularis .............................................................................................................................................................................5
4. Ovatus, ovatus-rectangularis ..............................................................................................................................................................6
5. Nutlet surface ornamentation type is reticulate-foveate..................................................................................................... S. sivasica
5. Nutlet surface ornamentation type is verrucate ........................................................................................................... S. tundjeliensis
6. Nutlet surface ornamentation type is reticulate or reticulate-areolate................................................................................................7
6. Nutlet surface ornamentation type is verrucate or scalariform ..........................................................................................................8
7. Reticulate...................................................................................................................................................................... S. mardinensis
7. Reticulate-areolate........................................................................................................................................................... S. laetivirens
8. Scalariform ................................................................................................................................. S. megalodonta subsp. megalodonta
8. Verrucate...................................................................................................................................................................... S. baytopiorum
9. Nutlet shape is ellipticus-rectangularis............................................................................................................................... S. subnuda
9. Nutlet shape is ovatus or ovatus-rectangularis .................................................................................................................................10
10. Nutlet surface ornamentation type is alveolate ................................................................................................................. S. siirtensis
10. Nutlet surface ornamentation type is reticulate ................................................................................................ S. viscosa var. viscosa
11. Nutlet shape is ellipticus-rectangularis........................................................................................................................ S. benthamiana
11. Nutlet shape is ovatus-rectangularis........................................................................................................ S. viscosa var. odontophylla